Effect of a Small Concentration of Iron Impurity on the Oxidation Behavior of Porous SiC

Oxidation behavior of porous SiC containing Fe was investigated using a quadrupole mass spectrometer by measuring the volume of evolved gases during oxidation at 1700K. This Fe-containing SiC was obtained by immersing the SiC in an acetone solution with an Fe(C5H7O2)3 concentration of 0.1M for 1-5min followed by calcination at 1173K. The weight gain and the total amount of gases evolved decreased with increasing Fe2O3 content. XRD intensity ratio of cristobalite to SiC was increased with increasing Fe2O3 content. These results indicate that the accelerated crystallization of amorphous silica to cristobalite and the retardation of the oxidation were caused by the added Fe.